Power transmission



April 20, 1943. w. P. WILLEI'TTI 2,316,926

POWER TRANSMI S S ION Filed March ll, 1941 INVENTOR 90 I v WARREN P. WILLETT s4 I [ATTORNEY I Patented Apr. 20, 1943 POWER TRANSMISSION Warren 1. Willett, Takoma Park, Md., assignor to Vickers Incorporated, Detroit, Micln, a corporation of Michigan Application March 11, 1941, Serial No. 382,804

3 Claims.

This invention relates to power transmissions, particularly to those of the type comprising two or more fluid pressure energy translatingv devices, one'of which may function as a pump and another as a fluid motor.

The invention is more particularly concerned with a power transmission system for operating a plurality of load devices exemplified by a hoist winch and wherein any one of the load devices may be operated at a time from a common'pressure source selectively by a combination ofvalves and pumpdisplacement controls.

In the operation of boat hoists aboard ship, it is frequently desirable to provide a common prime mover adjacent a group of boatuholsts for selective operation of any one of the hoists. It is also desirable to provide means for positively driving the hoist in a paying out direction so that the hoist cable may be lowered to pick up aboat. It

\ is also advantageous to arrange the drive so that one hoist may be operated to haul in its load at the same time that another hoist is being operated to pay out light cable. It is furthermore necessary that duringthe hauling-in operation the speed of hoisting be under absolute positive control as is also the case during paying out operation, whether the line be loaded or not.

I It is an object of the present invention to pro-' Ivide an improved hydraulic power transmission l system'adapted to meet these requirements with a minimum of complication and which is inexpensive and reliable and positivein its operation.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawin wherein a preferred form of the present'in'vention is clearly shown.

being understood that in the drawing and in the following description primed reference characters refer to corresponding parts associated with the valve 26'.

From the pump l8 a delivery conduit 28 connects with a second inlet port 30 of the valve 26 and the corresponding port 30. The end return ports 32 and 34, which are connected together through a passage in the valve body, are connected by means of a return conduit 36 with the tank I2. The ports 38 and) which lie between the inlet ports and the return ports are connected by conduits 42 and 44 with the opposite sides of a rotary fluid motor 66. The latter is adapted to drive a winch drum 46 for hoisting and lowering a load such as a boat.

The valve 26 is provided with a spool 50 having three lands 52, 54 and 56 which are arranged to control communication between the various ports in the well-understood manner. At the land 66 throttling grooves 58 are provided for producing gradual" opening and closing of communicationbetween ports and 34. The spool is biased to the left by a spring 60 and has a stem 62 at its opposite end carrying a cam-following roller 64.v

For the purpose of operating the valve an operatin handle 66 is pivoted at 68 and carries a cam hoisting position, a lever 14 is operated countertor I0, is positioned between two interconnected sump tanks l2 and I4 and is connected to drive at its opposite ends a fixed displacement pump 16 and a variable displacement pump l'8.

From the pump I 6 a delivery conduit 20, having the customary pressure responsive relief valve 22 connected therewith, extends to an inlet port 24 of afdouble-six-way, directional control valve 26. From the;port 24 a continuation of the conduit 20 extends to the port 24 of a similar valve 26'. The valves 26 and 26' are duplicates and are connected with the pump and the tank in parallel, it

clockwise.

stationary. The lever I4 is rigidly connected to a shaft 16 carrying at its lower end a lever I8. The latter is connected by a link with a sliding stop or control rod 82' which abuts against a roller 84 carried by the swinging yoke 86 of the pump l8. The latter determines the displacement of the pump l8, and, when it is in the position shown, that is, in axial alignment with the shaft of motor ID, the pump displacement is zero. As the yoke 86 is moved clockwise, the pump displacement is increased in proportion to the angle through which it is moved, The control stem 82 is biased downwardly by a spring 88.

The swinging yolee 86 is also under the control of a pressure responsive regulator 88 which com- When the handle 66 is moved down-- wardlyjo the lower position, the lever 14 remains prises a cylinder 92 in which a differential piston 94 is slidably mounted and biased upwardly by a spring 96. The latter is weaker than the spring 88 so that the spring 88 may always predominate over the spring 96. The stem 96 of piston 94 is connected by a link I to the yoke 86. The cylinder 92 is connected by a conduit I02 with the delivery conduit 28.

In operation, with the .motor lfl'running to drive the pumps l6 and I8 and with the parts in the position shown in the drawing, no fluid is delivered into conduit 28 by pump l8. The yoke 86 lies in neutral position. Since the discharge conduit 20 is blocked at the ports 24 and 24', the full delivery thereof is bypassed through the relief valve 22. This may be set at a relatively low pressure just sufficient to drive the motor 46 in a paying out direction.

When it is desired to haul in a load, the handle 66 may be operated in a clockwise direction, shifting valve spool 50 to the right and, at the same time, shifting the control stop 82 upwardly.

proportion to the amount of movement at handle 66 so that fluid is delivered into conduit 26 through ports 30 and 40 and conduit 44 to the motor 46. The latter is accordingly rotated at a speed depending upon the rate of fluid flow from the pump l8. Fluid exhausting from the motor 46 returns through conduit 42, ports 38 and 32, and conduit 36 to tank. 7

It will be seen that the hoisting speed is under complete control by the handle 66 and may be reduced or increased at will within the designed capacity of pump l8.

If, while the motor 46 is hauling in a load, it should be desired to pay out light cable at the motor 46, the handle 66 may be moved counterclockwise, shifting spool 50' to the left. This opens a passage for fluid from pump I 6 through conduit 20 to port 24', and from there through port 38, conduit 42', to motor 46'. The latter accordingly rotates in the paying out direction and returns exhausted fluid through conduit 44', ports 40' and 34 and conduit 36 to tank. The speed of rotationin the paying out direction is also under control at will by reason of the hoist winches and provide selective operation of any one of them in either direction and also selective operation of any two of them in-opposite directions.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. ma fluid power transmission system the combination with a variable displacement pump and a fixed displacement pump, of a plurality of fluid motors for operation selectively by fluid delivered by said first pump for one direction of operation and by the other pump for the other direction of operation, individual control valves for selectively connecting said motors individually with either pump for the corresponding direction of operation, said valves being connected with each pump in a parallel circuit, and means for operating said valves individually and simultaneously controlling the displacement of the first pump. l

2. In a fluid power transmission system the combination with a unidirectional delivery, variable displacement pump, of a plurality of fluid motors for operation selectively by fluid delivered by said pump, individual control valves for selectively blocking or opening communication between the pump and each motor, said valves being connected with the pump in parallel, individual operators for each valve, means for varying the pump displacement, a common connection between each of said operators and said means whereby the pump displacementmay be increased by operation of any operator in a direction tending to open its respective valve, and additional pressure responsive means for reducing pump displacement upon the attainment of a predetermined pressure independently of the throttling grooves 58 which'can be adjusted to restrict the exhausting fi'uid to any degree desired, thus causing pressure to build.u1 in the conduit 20 to the point where more or less of the delivery of pump I6 will be bypassed through reresponsive displacement regulator 90 acts in the usual manner in case of overload to reduce the pump displacement whenever a predetermined pressure is exceeded. 3

The conduits 20, 28 and and shaft 16 may extend to include as many duplicate valves as position of said operator. I

3. In a fluid power transmission systemthe combination with a unidirectional deliver-y, variable displacement pump, of a plurality of 'fiuid motors for operation selectively by fluid tion. tending to open its respective valve, saidconnection including a member extending adjacent each operator and a lost motion mechanism intermediate each operator and said memher, and additional pre'ssure responsive means for reducing pump displacement uponthe attainment of a predetermined pressure independently of the position of said operator.

WARREN P. WIILETT. 

